24:I[63208,["8920","static/chunks/8920-efbff8517d590b7e.js","9097","static/chunks/9097-7e60ff382fede0de.js","5914","static/chunks/5914-356082358a498a0b.js","9903","static/chunks/9903-11222066602aad8e.js","5438","static/chunks/5438-cfc6cd3ec63ed58c.js","3851","static/chunks/3851-d9d99b9df58ccefb.js","4621","static/chunks/4621-60797c2425663d2a.js","6871","static/chunks/6871-85cb03c97585f46a.js","6736","static/chunks/6736-932312a004c99faf.js","4550","static/chunks/4550-0bf059e3050c08b3.js","688","static/chunks/688-a6a2ac7bff269cd3.js","3984","static/chunks/3984-063c0b62f32133c7.js","7038","static/chunks/7038-4f87670d4e55ef18.js","9039","static/chunks/9039-75366c62dc7d0d0e.js","4563","static/chunks/4563-ad980d1babbf7b0b.js","6761","static/chunks/6761-0c10d1446de7ae1c.js","744","static/chunks/744-1e76229abb9e297b.js","7342","static/chunks/7342-1586df78600bf911.js","3617","static/chunks/3617-1f62a097637f4747.js","5895","static/chunks/5895-caa6c774914eb108.js","7481","static/chunks/7481-3b84c503a2ebfb3f.js","3668","static/chunks/3668-7dab69e4121c33af.js","39","static/chunks/39-e93a27d0920e6d92.js","2881","static/chunks/2881-445cc2384af2c6f9.js","2364","static/chunks/2364-e83d52fb21729d99.js","3208","static/chunks/3208-e65462d166bd3688.js","7582","static/chunks/app/toc/%5Btla%5D/%5Bvolume%5D/%5Bissue%5D/page-694a0e465c2c1334.js"],"default"] 25:T440,

HO₂•, usually termed either hydroperoxyl radical or perhydroxyl radical, is the protonated form of superoxide; the protonation/deprotonation equilibrium exhibits a pK_a of around 4.8. Consequently, about 0.3% of any superoxide present in the cytosol of a typical cell is in the protonated form. This ratio is rather accurately reflected by the published literature on the two species, as identified by a PubMed search; at the time of writing only 28 articles mention "HO2," "hydroperoxyl" or "perhydroxyl" in their titles, as against 9228 mentioning superoxide. Here it is argued that this correlation is not justifiable: that HO₂•'s biological and biomedical importance far exceeds the attention it has received. Several key observations of recent years are reviewed that can be explained much more economically when the participation of HO₂• is postulated. It is suggested that a more widespread appreciation of the possible role of HO₂• in biological systems would be of considerable benefit to biomedical research.

26:T544,

Biological systems rely on heme-proteins to carry out a number of basic functions essential for their survival. Hemes, or iron–porphyrin complexes, are the versatile and ubiquitous active centers of these proteins. In the past decade, discovery of new heme-proteins, together with functional and structural research, provided a wealth of information on these diverse and biologically important molecules. Structure determination work has shown that nature has used a variety of different scaffolds and architectures to bind heme and modulate functions such as redox properties. Structural data have also provided insights into the heme-linked protein conformational changes required in many regulatory heme-proteins. Remarkable efforts have been made towards the understanding of factors governing redox potentials. Site-directed mutagenesis studies and theoretical calculations on heme environments investigated the roles of hydrophobic and electrostatic residues, and analyzed the effect of heme solvent accessibility. This review focuses on the structure–function relationships underlying the association of heme in signaling and iron metabolism proteins. In addition, an account is given about molecular features affecting heme's redox properties; this briefly revisits previous conclusions in the light of some more recent reports.

27:T41c,

Hemopexin (HPX) is the plasma protein with the highest binding affinity to heme among known proteins. It is mainly expressed in liver, and belongs to acute phase reactants, the synthesis of which is induced after inflammation. Heme is potentially highly toxic because of its abi